Powdered detergents are well known commercial products in the laundry care industry. Detergents sold under the brand names Wisk (Unilever) and Tide (Procter and Gamble) have been available for many years.
Processes for manufacturing powdered detergents are also well known. In a typical process, a base powder formulation is passed through several steps wherein one or more agents are added. These agents can include, for example, perfumes, enzymes and colorants. It is not uncommon for commercial detergents that are marketed and sold under different brand names to have a common base powder, yet be different because they have different agents or additives. For example, brand A may have perfume X and enzyme Y, while brand B has perfume Z and no enzyme. It is also not uncommon for a single plant to be used to make several brands, even though those brands are unique. This can present scheduling issues because, for purposes of safety and quality control, it must be ensured that there is no cross contamination between the brands.
When processing powdered detergents, it has been found that a significant amount of agents can be lost prior to final packaging, particularly volatile agents such as perfumes. This is generally due the type of processes through which the powdered detergent is passed and the manner in which agents are applied to the base powder.
With reference to FIG. 1, a prior art process for manufacturing powdered detergents is shown. Base powder 100 flows from storage vessel 10 onto weigh feeder 20. Belt 22 moves the powder across weigh feeder 20, causing base powder 100 to cascade off belt 22 into vessel 30. Flow rates of base powder 100 can range from about 15,000 lbs/hr to about 100,000 lbs/hr. As powder 100 falls towards vessel 30, pressurized spray system 40 sprays liquid perfume P onto the powder, designated as powder 100P in vessel 30. Spray system 40 can include tank 42 containing perfume P, pressure pump 44 and spray nozzle 46. The rate of perfume application from pressurized spray system 40 is coordinated with the rate of flow of powder to ensure uniform dosing. Levels of perfume in the final product is typically in the range of from about 0.1 wt % to about 0.5 wt %.
From vessel 30, powder 100P is transferred to post dosing belt 50, wherein belt 50 further transfers the perfumed powder towards mixer 60, which is preferably a fluidized bed. Prior to entering mixer 60, various miscellaneous agents M2, M4 and M6 are added to powder 100P via vessels 62, 64 and 66, respectively. Agents that can be added to the powder moving along post dosing belt 50 include enzymes, colorants, sulfates, carbonates and other known additives. Typically, between 5 wt % and 25 wt % of the final powder composition can be added in this process. After addition of the miscellaneous agents, the powder is mixed in mixer 60 to ensure uniformity and is designated as 100P+M.
After mixer 60, powder 100P+M is transferred to vessel 70. Vessel 70 is preferably a hopper and serves to transfer powder 100P+M to one or more weigh flasks 80. The weigh flasks then gravity dispense a known quantity of powder (based on a weight measurement) 100P+M into suitable containers 90, such as boxes, bottles, buckets or bags.
Several inefficiencies can be identified with the process of FIG. 1, all relating to the application of perfume between weigh feeder 20 and vessel 30. First, the relatively high rate of powder flow from weigh feeder 20 requires a correspondingly high rate of flow of perfume from pressurized spray system 40. This can result not only in inefficient and uneven application of the perfume that can further result in clumps of powder 100P, but misapplied spray can accumulate on belt 22, hopper 30 and other equipment in the area. Second, when powder 100P travels along post dosing belt 50, at least some quantity of perfume volatilizes. Third, when powder enters mixer 60, the action within the mixer causes further loss of perfume, particularly if fluidized bed technology is utilized. Fourth, because between about 5 wt % to about 25 wt % of the final product is added after application of the perfume, the amount of perfume, on a weight percent (wt %) basis is higher for powder 100P than for powder 100P+M. This tends to exacerbate the above-identified inefficiencies. Fifth, when production of a first variant having a first perfume is complete and a second variant with a second perfume is to be manufactured, the production line must be cleaned from weigh feed 20 forward. Similarly, because the perfume is introduced early in the process and is able to enter the atmosphere at several steps, it is generally not possible to simultaneously run other variants in the same plant, for purposes of quality control. Lastly, losing perfume to the atmosphere results in economic and environmental costs.
Therefore, there is a need for an improved powdered detergent manufacturing process wherein the loss of perfume and other volatile actives during the process of making the powder is minimized. There is also a need to ensure uniformity of the final packaged product. There is a further need to increase plant efficiency.
Perfume agents can be classified by their relative volatility. High volatile perfumes are also known as xe2x80x9chigh notesxe2x80x9d while relatively non-volatile perfume are also known as xe2x80x9clow notes.xe2x80x9d High note perfumes are typically more perceptible by humans than low note perfumes, which is believed to be due to their high volatility. Known high notes also have a wider range of odors and, therefore, allow for greater flexibility when selecting perfume agents. Unfortunately, when manufacturing powdered detergents, it is the desired high notes that are typically lost during processing. This has resulted in a decreased amount of high note perfumes being used and, if used, less make it into the packaged product.
Therefore, there is also a need for a powdered detergent manufacturing process that would allow for increased usage of high note perfumes, wherein the highly volatile perfumes are retained in the powder so as to reach the consumer.
The present disclosure relates to a process which minimizes the loss of perfume and other volatile agents during the fabrication of powdered detergents. It has been found that it is possible to rearrange the order of addition or inclusion of volatile agents from one or more of the manufacturing process steps. More specifically, by adding the perfume and/or other volatile agents closer to the step of packaging, there is less loss of the perfume to the atmosphere during the process. In the case of perfumes, the perfume profile remains relatively unaltered and a wider variety of perfumes can be used.